Bonus points for supporting feed URLs with embedded http basic auth credentials. This is the core protocol that I think could lead to a decentralized web where people host their own private sites. It's also a huge motivator in my side project for running your own private blog with built-in private RSS: https://simpleblogs.org

edit: I've been experimenting with my own private blog's RSS feed which includes images, I would suggest you add `max-width: 100%;` for images to the CSS.